Development and validation of a new score for measuring post-operative complications

Assigning a numerical value to post-operative morbidity may improve its usefulness as an outcome measure. The recently developed Comprehensive Complication Index (CCI) is a step forward in this process but assigns an inappropriately high score to a combination of complications.

We developed a new score called the complication severity score (CSS) using a mathematical process and compared it with the CCI using a questionnaire-based survey of 49 experienced gastrointestinal and hepato-pancreatico-biliary surgeons. The CSS was modified based on the results of this survey and was correlated with other patient-centered outcomes in a prospective cohort of consecutive patients undergoing elective surgery.

Of the nine sets of scenarios, experienced surgeons' opinion matched with CSS in 6, CSS as well as CCI in 1, and neither CSS nor CCI in 2 scenarios. Of the total 441 responses, 281 matched with CSS while 143 matched with CCI (p = 0.0001, odds ratio: 3.7; 95% CI: 2.8 to 4.8). The modified CSS significantly correlated with the post-operative length of stay (r = 0.76; 95% CI: 0.68 to 0.82; p < 0.001), the length of ICU stay (r = 0.61; 95% CI: 0.50 to 0.70; p < 0.001) and with the difference between pre-operative and post-operative quality of life scores in the physical (r = 0.29; 95% CI: 0.14 to 0.42; p < 0.001) and social (r = 0.29; 95% CI: 0.14 to 0.43; p < 0.001) domains.

The CSS more often matched the opinion of experienced senior surgeons compared to CCI. The modified CSS significantly correlated with other patient-centered outcomes.